#include<iostream>
#include<vector>
#include<string>

using namespace std;

int main() {
	vector<char> numbers(3);
	int x = 0;
	for (int i = 0; i < 3; i++) {
		cin >> numbers[i];
		if (numbers[i] == '?') x = i;
	}

	char answer;
	for (char number : "14") {
		numbers[x] = number;
		if ((numbers[0] < numbers[1] && numbers[1] > numbers[2]) 
				|| (numbers[0] > numbers[1] && numbers[1] < numbers[2])) cout << number;
	}

	cout << endl;

    return 0;
}